Gary Dierking Outrigger Canoes

Based on my other recent thread I started looking through the pdf I found online of Gary Dierking‘s book on outrigger sailing canoes while I wait for my paper copy to arrive.

The Ulua is 18ft with a hull weight of 64lbs (3.5lbs/ft) and fully rigged weight of 122 lbs.

The Wa’apa is 24ft with a hull weight of 174lbs (7.25 lbs/ft) and fully rigged weight of 275lbs. Each 8ft section of the wa’apa (58 lbs) is almost the same weight as the entire Ulua hull.

Does the strip construction vs plywood stitch and glue construction really make that much of a difference in weight or is it due to the multi-sections of the wa’apa needing extra bulkheads that don’t exist in the Ulua?

The wa’apa has a “lightweight” construction that uses 3/16 as opposed to 1/4” ply for the sides so that may reduce the weight of each section to ~50lbs. Still seems excessive in comparison to the Ulua.

I think I’d rather take on the stitch and glue wa’apa due to the shorter construction time, but not sure I’d be happy with the weight of it in comparison to the Ulua or Wharram Melanesia (which others pointed out some issues with).

What am I missing here?

 

Primarily the strip built hull is lighter per square foot of hull area and there are fewer square feet of hull area. The bulkheads and framing do also contribute to the weight difference.

 

I mean, that’s why I normalized the weights to length. 3.5lbs/ft length with the strip vs. 7.25lbs/ft length for plywood. Without the center section both are close to 16ft. Seems like they should be relatively similar in other dimensions (from someone that doesn’t know boats that well).

The Ulua hull is 15% narrower (3”), but that’s would account 4.1lbs/ft.

Does the curvature of the hull with the strip construction really halve the surface area? Or are the sides lower and it’s just an all around smaller boat in every dimension.

Looks like the overall width (with outrigger) is 6.5 vs 11 ft. So maybe the wa’apa is really just designed as a much larger boat. Clearly I didn’t realize that from the original question.

 

You are correct, the wa'apa is a much bigger boat. I pulled Gary's book (a go to reference) off the shelf to refresh my fading memory.

It would be instructive to sketch the hull profiles and cross sections at the same scale for comparison. The curved cross section and strongly rockered hull of the Ulua cover fat less area than the rectaliner Wa'apa which also has substantially more deck area.

 

From what I understand, the difference in weight mostly comes down to how the boats are built and their design. The Ulua’s single hull is light because it’s smaller and simpler—strip construction can be really efficient with materials.

 

the waapa isn't stitch and glue, you could make it lighter by making it a one piece and maybe using the stitch and glue method?

I've nearly finished my main hull - I'd be surprised if it weighs less than 125kg (but it's beefed up a bit and fully sheathed)

 

I think mr Dierking was against s&g construction for his hulls due to resultant chine unfairness which may occur.

Regarding the weight difference I feel the Ulua to be in the paddling canoe territory while the waapa is more of a small trimaran/outrigger more suitable for small outboard motor, even if it can be paddled quite efficently.

 

Its worth noting that 1/4 inch of white cedar sheathed with 6oz cloth both sides is about the same weight as 6mm unsheathed okoume plywood (eg joubert). Both weigh about 9oz per square foot. As a guess I would say the weights quoted for wa'apa are for sheathed meranti or fir, and if you were to build in unsheathed Okoume you could would up with a much lighter craft. Ulua has less surface area, so you're not going to be that light, but you could probably shave about 1/3 of the weight off the main hull.

 

Even so, a 24ft big volume (on the canoe scale) ply hull that weighs 150kg is still pretty light.
Nobody is car topping a 24ft anything - a few extra kg is probably not that big a deal?

 

I used to easily cartop a 24' marathon sit on top "Almost There" regularly. Now sometimes its a stretch to load a 12' solo canoe ;-)

 

I was looking at the 16ft version of the wa’apa for car topping.

Thanks, that’s good information and something I’ve been wondering about.

My son wants to be able to paddle and sail. And I need to be able to cartop it at least initially. We’ve got smaller vehicles and have a few years left on all of them. Not ideal, but need to make do with what we have.

 

You can do a plywood Ulua, it has been done before. Car toppable too. wikiproa / Daves Ulua Tacking Outrigger Canoe http://wikiproa.pbworks.com/w/page/29971151/Daves%20Ulua%20Tacking%20Outrigger%20Canoe

Shrinking one to 16ft wouldn't be a problem, just remove some length from the middle of the hull, you move the molds in the middle closer together. For a plywood version you do this digitally.

 

In that case the most logical course of action would be to build 2part 16ft Wa'apa and leave the possibility of adding central 8ft section sometime in the future if deemed neccesary.

 

A sheathed both sides cedar boat with say 6 oz glass is not 50% of the weight of plywood.

And you cannot normalize boats and get a weight per linear foot!

One can also not compare thicknesses of ply boats to strip boats and suggest much of anything.

You can compare weight to displacement, but even then one must ask the purpose of the design. A 24’ boat is capable of bigger seas than a 16’, but must be made stronger (and weigh more).

So, the comparison is really unfair and invalid.